Tanis I secured by Tau

By early 022M42 the Tau empire had built up significant forces in the Hadron Expanse after several years of patient planning, and the focus once again fell on their "Hadron Expansion Sphere". With their base at Echo Reach now a veritable stronghold, and having secured Dnatha, Awarath, Mimir and Hussaria with some limited help from the Federacy, the commanders of the Tau Empire planned the next phase.

There was some disagreement in Tau high command over the relative priorities of their campaigns, with some favouring the system of Boltarean which they contested with chaos forces as the primary goal, while others saw the importance of securing a base in the Hadron Deeps - close to the rich new resources of the Rifts of Hecate, as higher priority. In the end the Tau waited until their forces were capable of acting independently in both theatres, so in 02.022M42 the Tau Empire began new offensives in both the Tanis and Boltarean systems.

On Tanis I the Imperium had already established a base, defended by on of the Knightly Houses. A key world in the system, on 1202.022M42 the Tau invaded in strength, deploying a full hunter cadre in opposition to the imperial defenders. The battle for key objectives was brutal, but Tau firepowere eventually prevailed, forcing the remaining Knights and their allies to abandon the world rather than risk annihilation. The first part of the new two pronged Tau offensive was going to plan.